Electrical production of light.



P. 0. HEWITT. ELECTRICAL PRODUCTION Q]? LIGHT. APYLIUATION FILED MAY 2, 1912.

T 1 1,562., Patented Sept. 15, 1914.

v l/dI/E/I/TOR l 1 BY 64mm 0 W ATTORNEY State of New Jersey;

UNITED STATES PATENT OFFICE.

ilsszenmnizrs, 'ro dema HEWITT, or Bmeyqooiinmop, lilfljfijfltlifiltf, Aslsioiroit, BY MESNE miwrrr ELECTRIC comumr, or HOBOKEN, NEW

JERSEY, A. convention on NEW JERSEY.

uncr tical; ritonn'c'rio'it or train.

sse tmtmda a: Letter: fat-eat.

Patented sept. 15,1914.

fll'iglnal application filed A1511! 11-, 1698; Serial-11o. 177,199. Divided and this application filed May 2, 1912.

' Serial-110194348.

To all whom it may concern: 1

Be it know-nthatL-Pnran Goornn I-I'mwrrr, a citizen of the United States, and resident of Ringwood' Manor, county of Passaic, have invented certain new and useful Improvements in the Electrical Production of Li' ht,- or which the foll'owin'g' is a specification:

The object ofmy invention isto provide a newand useful meanswf producing light by electricity, whereby a light ofhigh' illu'- mutatingow-er is roduced; and the; intensity and color of thelight may be varied-.-

I have"- discovered that certain vapors-of specific density and physical condition have e property of becoming intensely light radiant when air electric-,current is passed through them. Such a vapor, is the: vapor of mercury, sediuih, iodinand other metals, each produeing a light with colors eculiar to itself. The light giving quality depends ehiefly'on thedensity of the vapor,- as well asthe metering-it being most intense atthe roperty to a certain extent,

"them are objectionable on account. of the point oii saturation, or boiling point of the metalgthe light giving qualit being somewhat ro brtionetl to the densityw Besides simple metallie' vapors, other gases have this but most of temperature necessary, and also'onaccount ofthe electrical resistanoeat thepoint Where their vapor is the physical state,- which allbw'sthem; to be light radiant. For these reasons their use in many cases is impracticabl'e; In the case of mercurywhien is a fair exa ple of a metal volat'iliiing at a practical temperature, and vapor is inclosed or formed in a] whose ends are turned down so as to holda globule of mercury, ilit'o which are led w'ires'fo'r conductingthe electrical current, Whieh wires may be sub merged in thevolatilizabl'e'material or'not, as

desired; In case thewire or electrode proje'cts through the material to be'yolatilized, the Wire becomes heated on' the discharge of an electric current, which in tiiril heats the material to be volatilized and yol-atiliaes it, fillin the tube with its vaporyif the tube is not already of such a' temperaturethat it is not suflicientlyfull of vapor. Itiswell known that a Wire leading into anattenu ated' atmosphere becomes heated, 1 although the'same sized wire will conduct the current under ordinary conditions without heating.

In the where the material to be volatihzedconstitutes the electrode, the current heats the electrode direct, producing the effect. A tube may be constructed contaming an exact amount of vapor (or materialto produce the vapor) necessary to produce this intense light electrically, in Whi'chcase the'exact degree'of vapor density and physical conditions can be produced which-is most advantageous. The electrodes must bemad'e of'such size as not to deteriorate by the'el'ectrical discharge: The light action of these tubes isintermittent and the electric current im uls es or oscillations can bemade with the' equency desired, and so rapid as to require a most delicate instrumerit to detect that thelight is no continuous A tubein the form described, one quarter of an inch in diameter, one foot in length will produce a light too' brilliant to look at,the light bein'g morethan a hundred candle power. Thequantity of light may be varied by the current used, from great brilliancy to the bare luminositywof ordinary vacuum tubes or Geisler' tubes. This tube is practically indestructible, having nothing to rain or destroy, operating at somewhere about a temperature'of 300 6., if mercury is usedz- I'n the'casewh'ere other metals or materials" are used, my tubes operate at the temperature a little above the boiling point orthereabouts,'of' thesubst'ance in a vacuum. It is-advisableto usea substance which Volatilizes at ordinary temperatures as near as possible, for economy. The metal rhubidiuih gives a deeperred light than any other, and I prefer to use this metal or a metal having 'a deep red band in the spectrum, or a proportion of this" metal to obtain a deeper red color in my tubes. Potassium, also 11thiuni giye fair results, the temperatures being higher. In practice a more agreeable light will be produced by the judicious use oftwo or' more tubes, each containing different vapors,

In order to more fully' explain my inventipn, reference is had to'the accompanying drawing forming a part of the specification,

in which similar characters of reference inhappens through accident. At a and ig. 3 is a longitudinalisection ofa strai ht tube having a volfiihiable mag teriaf atone end only. I

A is an electric generator, B is acon verteIyGa condenser, D II yigires tenninating in electrodes E E, extending'into the volatilizable substance,.-l3, contained in the bulbs G Gr of the vacuum tube. Q.

To operate my light, I: use an eli'c ric current of varying voltage, having" 4" nd that from 500 to 5000 voltsmost successful, but it can be operatedat 'mangi'dth'er. electrical pressures, depending on 't' 6. length of the tube G desired tooperatgi-a'nd'the'quantity of light to be produced ralso for the imaterial used. I place across the wires D leading to the tube G the condenser C which is of suitable capacity; the object of the condenser being to accumulate the electric .c-urrent during the minute period of time when the current is not passing through the tube G, and deliver the accumulation to thetube G during the time the tube is taking-current. The condenser also aids the light giving quality of the tube. This condenser C being in resonance with the tube G and current, will adjust the voltage. of the current in some degree to any varying resistance that may occur in the tube. The tube itself is a condenser of certain capacityunder the condition that I establish, and under light giving conditions is oscillatory or intermittent, acting somewhat as a discharger for the condenser, producing waves or pulsations in the current from .the condenser. The tube G is constructed with the volatile electrodes G G and is proportioned in size to the current to be used. The resistance of the vapor in a high degree of attenuation is greater than it is when it becomes a little more dense; then becoming more dense the electrical resistance increases so that if the electrodes overheat, the vapor generated willshut off the electric current until they are again sufiic'iently jcool,,but

with a properly constructedtube, this only pressure the electrical resistance of vapor decreases as the temperature increases;-

In order to produce one of mytubesfl first exhaust it to a high vacuum, hot, then; turn on the electric current and while the current is on, cause the absolutely pure vapor to flow through the tube, or generate in the tube and flow into the pump until it has carried away with it all the impurities existin in the tube. When this is accom-j plishe at the required vapor densit I (pressure and". temperature), the fact, ecomes self-evidentby' the. great quantity an? light coming from the tube. The quantity of light 1s approximately proportional to the vapor density. The quantity of light is under absolute control, electrically or other:

side. iql evationof a modified film or tube;

' a su arms 1? as to amid-the fin' the tube- 'is'yv metals that yola constant wisef: "l have found it advantageous, evenwhen op'erat ng tubesmt almost ,atmosiphgg c, ,oiprevent ra iatlon be radiated from the tuba-,1 have a some- What corresponding increasedwproduction of light. ,These tubes'mambeqnade 1n almostany shape from spirals tostrai ht tubes, or

inverted U-shaped tubes, or U.- aped tubes; but in the case of a U-shaped tube used for volatile material.

' Inforder to equalize the pressure within;

the ;tube, I may provide the same with a reservoir G in communication with the interior of the tube to be filled with vapor, which, however, is not affected- 11 the current and rendered luminous, as t e current does not pass through it,- and hence the va por contained therem 'can act as an equalizer to give the lights. uniform brilliancy and steadiness.

Fig. 3 shows a straight tube with a vola tilizable substance at the lower end, anda 10o solid piece of-iron or the like suspendedgin the upper enlarged end,,-e lec'tricwiresdead ing to the substance and the; jiece of'iren; The electrical resistance: 0 -..%Varying saturated vapors variesjin' a very; great degree for the .same density, mercuryjvapor being of, comparatively ;-low resistance and iodin vapor of high resistance. L-preferto use vapors of low electrical --re s istancej-as more economical and'convenient; 'giIn producin my tubes containing; mercury Ij l1awe-ioun that a very small amount of oxygen or oxid of mercury in the tube increases in a, marked degree the electrical. resistance and impairs thelight radiating quality l I have "also 11:51

found that the combination of two.- or..more

tubes, each givingrays Oifi ight of =1 i ferent color, is advantageous..-

This application is a division of plication filed ber -677,199.

I I-claim as my invention:

1. The method of operating 'gas or vapor electric lamps having a mercury 'cathode and an anode-therein which conslsts in ap- 125.

plying tothe electrod s .1 electricpotential. exceeding 500,-.vo1tsaper-foot; of luminous column, ff V i 2. The method of operatinggas or vapor electric clampsihavinga{ mercury cathode q r ja t oss; Asthe vapor "eattefiua'tedfin the case of an. id" above the atmospheree 't'efmperatur'f ifinay "become necessary in .the economical use of some of them to'use .a'starting device, to acquire the proper vapor density on startingI' Sueh:a startm' -=de-f 75 vice-may consist of applied or external eat mir ap- Aprll 11, 1898, Serial um- 1 2 0 and an anode therein, the dimensions of the lamp bein approximately 1 foot in length and 3; inc in diameter which consists in applying to the electrodes an electric potential exceeding 500 volts per foot of luminous-column.

3. The combination of a vapor electric lamp, comprising an exhausted container, a vaporizable electrode material therein, said lamp operating at a relatively high vapor pressure, and special means for automatically bringing the vapor pressure in said lamp from the low pressure inoperative condition to the high pressure operating condition. g

4. The combination of a vapor electric lamp comprising an exhausted container, a vaporizabl electrode material therein, said lamp operating at a relatively high vapor pressure, and special means for automatically bringing the vapor pressure in said lamp from the low pressure inoperative condition to the high pressure operating condition, said means comprising a resonating electrostatic capacity connected with the supply circuit to the lamp. 1

5. The method of operating electric apparatus comprising an hermetically sealed container, a mercury cathode and an anode, said container volts in a quarter inch tu being exhausted to a high degree of purity which consists in raising the, temperature ofthe cold lamp until the starts" ing resistance falls and then maintaining the tupe at a vapor density requiring at least 500 volts per foot of tube.

6. The method of operating electric apparatus comprising an hermetically sealed container, a. "mercury cathode and an anode, said container being exhausted to a-high degree of purity which consists in raising the temperature ofthe cold lamp until the starting resistance falls and requiring a voltage in proportion of at least 500 V0 t of quarter inch tube.

7. The method of operating electric appa: ratus comprising an hermetically sealed container, a mercury cathode and an anode, said container being exhausted to a high degree of purity which consists in raising the temperature of the cold lamp until the starting resistance falls and maintaining the lamp at the condition re uiring at least 500 Signed at New York in the. county of New York and State of New York this 25th day of April A. D. 1912.

PETER COOPER HEWITT.

Witnesses:

F. E. BARNES, R. A. HEWITT.

s per foot a foot in length. 

